Recent studies suggest that 2.4 % to 5.6 % of pregnant women are physically abused each year in the United States. Domestic violence is hypothesized to cause adverse pregnancy outcomes through two mechanisms: physical trauma and prenatal stress. To date, research into the association of domestic violence in pregnancy and adverse birth outcomes provides inconsistent evidence. Most studies, however, have been small in size, used an endpoint of low birthweight, and focused primarily on low-income women, who are at highest risk of both domestic violence and adverse pregnancy outcomes. We propose to conduct a population-based case-control study to investigate the independent and joint effects of domestic violence and prenatal stress on the risk of preterm delivery (N=950) and intrauterine growth retardation (N=1210). In addition, patterns of abuse will be examined over three points in time (prepregnancy, pregnancy, postpartum) among control subjects (N=950) to determine if the pregnancy or postpartum periods are high-risk times for domestic abuse. The influence of contextual factors, such as pregnancy intendedness, will also be examined. The study population, identified from the Iowa live birth certificate file, will be comprised of residents of three Iowa counties who deliver between August 1, 2001 and July 31, 2003. Domestic violence and prenatal stress will be assessed using well-tested, established instruments, including the revised Conflict Tactics Scale (CTS2) and the Prenatal Life Events Scale. Data will be collected using computer-assisted telephone interviews, covering the primary study exposures and risk factors for domestic violence and the two study outcomes. Subjects will be interviewed 3 to 6 months postpartum and compensated for their participation. Medical chart abstractions will be conducted to validate case definitions and document prenatal care variables, medical history, and pregnancy complications. With at least 80 % power, the study will be able to detect increased risks of 2.0 for the least prevalent exposure, domestic violence. This study will be the first to examine the effect of prenatal stress in conjunction with domestic violence on adverse pregnancy outcomes, and offers a unique combination of methodological and conceptual strengths to address these issues.